Evaluation of an experimental hot asphalt concrete urban paving section using construction and works demolition waste (CDW) as a coating layer

Abstract

Objective of the study: To present a proposal for the application of construction and works demolition waste (CDW) in the manufacturing of asphalt coating as an alternative for the use of these materials.

Methodology/approach: Physical, chemical and mineralogical characterization tests and dosage assessments by the Marshall method were applied. An experimental pavement stretch was then analyzed using a market feature adapted for CDW inclusion. Recycled aggregate (RA) containing gravel 1 and sand was then used to replace the same natural type of aggregate in an asphaltic coating layer.

Originality/Relevance: On a worldwide scale, the building materials industry is expected to increase two and a half-fold between 2010 and 2050 (UNEP, 2002). In Brazil, estimates indicate that the construction sector will double in size by 2022 (Cebeds, 2009), leading to increased waste generation. It is, thus, crucial to take measures aimed at solid waste management through cultural and technological changes, aiming to meet the needs of a society increasingly elucidated and demanding in regard to environmental preservation. One of the engineering sectors that can promote the use of RA, which requires less investments, is that of urban and road pavements (Rezende et al., 2016).

Main results: The proposed experimental program indicates that CDW aggregates exhibit adequate potential for use in hot asphalt coatings, based on volumetric parameters, Marshall dosage tests and experimental stretch assessments, in which traffic analyses and bearing conditions indicated quite satisfactory asphalt pavement results.

Theoretical/methodological contributions: During the analyzed period, only slight functional differences were observed between RA and non-RA containing asphalt coatings. Thus, the well-dosed use of a material that may result in environmental pollution on a low traffic-load pavement becomes viable from a sustainability point of view, due to reduced consumption of natural aggregates in the face of the benefits of recycled material.

Conclusions: The gravel 1 RA was adequate for asphalt pavement use, exhibiting some interesting properties, i.e. Los Angeles abrasion (35%) and shape index (0.87), in accordance to current Brazilian ABNT standards. Regarding the experimental stretch, although a small detachment of ceramic surface portions was observed, this subtle occurrence did not compromise the asphalt coating and, after 5 months of functional analyses, the asphalt pavement continues to perform very satisfactorily regarding vehicle bearing.